Abstract: A hydraulic operating system for a series of dockboards mounted on a loading dock. Each dockboard includes a hydraulic cylinder unit that is employed to elevate the ramp, and a single hydraulic pump unit is utilized for the series of dockboards. A discharge line is connected to the outlet of the pump unit, while a return line connects the inlet of the pump to a reservoir, and individual supply lines are connected to the hydraulic cylinder units of each dockboard. A multiple position valve interconnects the discharge line, the return line and the supply lines and is operable to selectively direct hydraulic fluid through the discharge line to at least one of said supply lines to operate the corresponding cylinder unit and elevate the ramp of that dockboard, and for simultaneously connecting the other supply lines to the return line.

Abstract: A ramp construction for a dockboard. The ramp includes a deck plate supported by a series of spaced generally parallel beams. Each beam is a formed metal structure composed of a pair of side members having diverging ends that are secured to the underside of the deck plate, and a generally horizontal base section which connects the lower extremities of the side members. Generally vertical plates are secured to the forward end of each side of each beam, and the plates project forwardly beyond the ends of the beam and are provided with hinge openings that receive hinge pins to connect the lip of the dockboard to the forward edge of the ramp.

Abstract: A frame construction for an adjustable, pit mounted dockboard. The frame includes a rear frame section and a front frame section which are connected solely by a tubular housing that contains a spring for the ramp counterbalancing assembly. Leveling members are adjustably mounted for free vertical movement on the base member of each frame section, and after levelling of the frame in the pit, the leveling members are welded to the frame sections to support the frame in the leveled condition.

Abstract: A return-to-dock-level mechanism for a dockboard. The dockboard includes a ramp which is hinged at its rear edge to a loading dock and a lip is hinged to the front edge of the ramp and can be pivoted from a downwardly hanging pendant position to an extended position flush with the ramp surface. The ramp is adapted to be moved from the horizontal cross traffic position to an upwardly inclined position by a counterbalancing spring assembly, and a uni-directional holddown mechanism will prevent upward movement of the ramp unless manually released through operation of a cable. An operating link is supported by the ramp and has one end attached to the holddown cable. When the ramp is walked down to a below dock level position with the lip extended, the link is moved to a latched position.